The inventive concept relates to semiconductor memory devices capable of performing a partial self refresh, and semiconductor memory systems including this type of memory device. More particularly, the inventive concept relates to semiconductor memory devices not performing (or “excluding”) self refresh for a specific region identified by an address while performing self refresh for other regions, as well as memory systems including same.
Data is stored in memory cells of many volatile semiconductor memory devices, such as dynamic random access memory (DRAM), by storing a corresponding level of electrical charge on a capacitor. This charge must be periodically restored (or “refreshed”) to avoid the loss of data, since the stored charge inevitably leaks from the capacitor over time.
Accordingly, some form of refresh operation must be used in conjunction with volatile semiconductor memory devices and constituent memory systems.